Natural uranium and thorium distribution of teas in typical regions

Objective: To acquire the content and distribution level of natural uranium and thorium in typical regional teas, and establish microwave digestion-high resolution inductively coupled plasma mass spectrometry method to determine uranium and thorium in tea samples. Methods: Taking 20 kinds of teas produced in 15 provinces as samples, high resolution inductively coupled plasma mass spectrometry was used to analysize uranium and thorium after microwave digestion. Results: The limit of detection for uranium and thorium was 11 ng/L and 8.0 ng/L, respectively. Their recoveries were between 97.5%∼ 102.0% and 96.9%∼102.3% for uranium and thorium. Conclusion: Uranium and thorium content of teas have some differences in the regional distribution, and teas from the western and south central regions have higher uranium and thorium content than that of east and south regions. (authors)